Amine functional and cationic latex polymers have been the subject of a significant amount of research because of the anticipated advantages of these materials in several important application areas. Such polymers may well be suited for use as flocculation and paper additives, coatings and adhesives, etc. Only a few methods of incorporating reactive amine functionality into aqueous latex polymer compositions have been developed. The methods usually require specialized compositions and processes. The following patents describe various procedures for obtaining polymer compositions containing amine and amine/ester functionality.
U.S. Pat. No. 5,326,809 describes aqueous polymer emulsion compositions formed by the emulsion polymerization of unsaturated monomers stabilized with an amine functional water soluble polymer based on N-ethenyl formamide. The water soluble amine containing polymer is formed by the polymerization of vinyl acetate and N-vinyl formamide and the subsequent hydrolysis thereof.
U.S. Pat. No. 4,988,762 discloses aqueous self crosslinkable coating compositions based upon polymers formed by the polymerization of a vinyl monomer having carbonyl functional groups and amine precursor groups. Typically, the amine precursor groups are carboxyl, oxazoline or ketimine groups. Examples of carboxyl containing monomers include acrylic and methacrylic acid; maleic acid; oxazolines include 2-isopropenyl oxazoline; ethylenically unsaturated ketimines are derived by the reaction of a ketone with an amine followed by the reaction with an ethylenic derivative. The oxazolines and ketimines may be converted to amines via hydrolysis. The polymer may be prepared by emulsion polymerization.
U.S. Pat. No. 4,668,748 discloses crosslinkable amine functional polymers which are prepared by the solution copolymerization of an aromatic sulfonate monomer with an amide containing monomer in water. The amide is then transformed to the amine based on the reaction with a strong base and hypochlorite, known as the "Hofmann reaction." Polymers prepared according to this process can then be crosslinked by reaction with an aldehyde such as glutaraldehyde or formaldehyde.
U.S. Pat. No. 4,818,341 describes the beneficial properties which can be imparted to paper through the use of a primary amine functional water soluble polymer, optionally in conjunction with a modified starch polymer. The polymers are formed by polymerizing N-vinyl formamide alone or in conjunction with other monomers in amounts of up to about 25% by weight as solutions or water-in-oil emulsions followed by hydrolyzing N-vinyl formamide units. Hydrolysis is effected by contacting the polymer with an acid (mineral or organic) followed by neutralization with free base.
U.S. Pat. No. 4,957,977 discloses the preparation of vinylamine copolymers and their use as flocculating agents, paper additives, etc.. The polymers are prepared by polymerizing N-vinyl formamide using mass, solution or precipitation polymerization. The formamide groups are converted to amine groups by hydrolysis in acidic aqueous medium at temperatures from 40.degree. to 100.degree. C.
U.S. Pat. No. 3,715,336 discloses vinyl amine/vinyl alcohol copolymers prepared by the hydrolysis of a vinyl carbamate/vinyl acetate copolymer. These polymers, which are suited as flocculants for the clarification of aqueous suspensions and as wet strength agents for paper when combined with epichlorohydrin, are prepared by forming an interpolymer of an ethylenically unsaturated monomer and an alkyl N-vinyl carbamate. Interpolymers of vinyl acetate and the alkyl N-vinyl carbamate are converted to vinyl amine/vinyl alcohol copolymers by dissolving the copolymer in aqueous acid.
U.S. Pat. No. 4,255,548 discloses copolymers of ethylene and vinyl amine for use as flocculants for water clarification. The polymers are formed by polymerizing ethylene and N-vinyl acetamide in an alcohol medium. The resulting copolymer is then hydrolyzed by contacting the copolymer with a molar excess of aqueous mineral acid at temperatures of 75.degree. C. and above.
U.S. Pat. No. 5,086,111 discloses the preparation of amine functional polymers containing acetal groups prepared by the hydrolysis of an N-vinyl formamide/vinyl acetate copolymer. Hydrolysis is effected by acid or base catalysis in methanol and water.
U.S. Pat. No. 4,921,621 discloses hydrolyzed copolymers of N-vinyl amide and acrylamide for use as water loss control additives and drilling muds. The copolymers are formed by polymerizing an N-vinyl amide, e.g., N-vinyl acetamide or N-vinyl formamide with acrylamide via inverse emulsion polymerization followed by hydrolysis of the copolymer in water at elevated temperatures ranging from 60.degree. to 80.degree. C. Either acid or base hydrolysis can be utilized.